A man has been found dead in Whyalla, South Australia, after five days of heatwave conditions.

The body of the elderly man was found in a park in Bowden Street, Whyalla, after police were alerted by a member of the public about midday.

It is believed the unidentified man suffered existing health issues and may have succumbed to the hot conditions being experienced in the region.

A Country Health SA spokesperson said it was hard to determine if deaths were heat related and confirmation would not be available for some time.

An investigation will be undertaken by the coroner’s office to determine the exact cause of the death of the man who was known to police.

The week of heatwave conditions have taken their toll on South Australia which has been under a deluge of 40+ degree weather since Monday.

South Australian hospitals have seen 219 heat related admissions since the beginning of the week including 25 people in regional areas.

Firefighters have been battling outbreaks in extreme heat conditions across the state since Tuesday and hospitals, libraries and bus stations have opened their doors to the public seeking relief from the heatwave.

Fire bans in place for Friday

Fire bans have been issued for the whole of South Australia for Friday, the second day in a row, as the Bureau of Meteorology warns of a weather system which has the potential to reignite and fan fires.

Forecast brings hope for South Australians

Weather for Friday has been forecast as hot with dry conditions and north to northwest winds reaching 30 to 45 kilometres per hour ahead of a gusty southwest to southerly change.

Towns from Wudinna to Kingscote and Robe will be the first to get the fresh and gusty southwest to southerly change late morning while Cleve to Adelaide and Keith can expect a change late afternoon.

Woomera to Hawker to Renmark will have to wait until the evening for a cool breeze.

Rain is also on the horizon with a chance of showers and thunderstorms in the south and west.

Patchy rain has been forecast for the far north and widespread rain is predicted about the northwest border where there is the possibility of heavy rain.

A low weather trough brought a thunderstorm front through South Australia on Tuesday and with it more that 54,000 bolts of lightning and strong winds which have fanned fires across the state.

According to the Bureau of Meteorology the heatwave by Thursday was focused mainly over southeastern Australia.

Severe heatwave conditions were expected to round off the week southeastern South Australia, southern NSW, Victoria and Tasmania with extreme heat persisting across inland Victoria,the far southeast of NSW and inland Tasmania.

Prepare to act

With severe and extreme fire danger warning the Country Fire Service urges residents living in one the 185 bushfire-prone areas to check their Bushfire Survival Plan, be ready to act and know the hierarchy of places they can go which can offer safety.

Coping through the heat

University of Adelaide School of Population and Health researcher doctor Sue Williams said a study of rural and regional communities showed many people coped well during hot days but heatwave conditions produced new challenges including stress from the threat of fire.

The elderly, disadvantaged, people with health problems and outdoor workers were seen as the most vulnerable as were tourists and immigrants who were not used to the heat of an area.

Housing built without thermal inefficiencies, distance and lack of facilities were some of the disadvantages outlined in Ms Williams' study.

"The smaller communities have fewer options for people to seek relief from the heat such as a library, swimming pool or shopping centre," she said.

"Many people live a distance and find it hard driving in the heat to access somewhere cooler."

Barriers people faced included limited transport, the increasing cost of power and the elderly who do not like to use air-conditioners.

But the study also outlined many advantages to sitting out a heatwave in the country.

"Some of the advantages are the quite strong networks within communities," she said.

"People are more likely to check on their neighbours and the elderly. People also feel more safety in opening the house in the evening to get some cooler air than those in the city."

Watch and act message

With temperatures soaring, police patrols will be on the watch across all regions for arsonists as part of Operation Nomad.

A South Australia Police spokesperson said police urged the public to remain vigilant of the dangers of bush fire and contact them on 131 444 if they noticed any suspicious activity in the fire danger areas from people or vehicles.

Country Fire Service spokesman Chris Metevelis said deliberately lit fires from arsonists were a concern.

“Firebugs are a concern, not only because they start fires but they also put communities and our firefighters and volunteers at risk,” he said.

"Known firebugs don't change the way we operate but it does for the South Australian Police – they put on extra staff for operation Nomad."